This present invention relates to an apparatus and method for dispensing materials formed from components that should not be mixed until immediately prior to use. More specifically, the invention relates to a device and method for mixing a first component with a second component that causes a chemical reaction to take place.
A variety of materials are made of two or more initially separate components that are preferably not mixed until immediately prior to use. Examples of such materials include two reactive component polymers such as epoxies, polyurethanes, polyesters and silicones. In many instances, such two-component materials may unduly cure, harden or become otherwise unsatisfactory for use if mixed too far in advance of the actual time that the material is applied to the work site. As a result, the components are housed in separate, isolated containers.
The isolated containers for each component can be housed in standard sized, elongated disposable cartridges that are received in caulking guns or similar devices such as those disclosed in U.S. Pat. No. 3,323,682 to Creighton, Jr. et al. and U.S. Pat. No. 4,676,657 to Botrie. These cartridges can comprise a tubular cylindrical outer body with top and bottom ends. The top end contains an integral or detachable dispensing nozzle, while the bottom end permits access to a movable plunger that retains the materials within the body and provides a surface for the caulking gun to act against when applying dispensing pressure to the contents of the cartridge. The housing includes at least two internal reservoirs. Each of these reservoirs houses one of the components to be mixed and dispensed. In order to dispense the contained components, the disposable cartridge is securely positioned in the caulking gun or similar device as is known in the art. The action of the caulking gun on the plunger at the rear end of the cartridge causes the contained components to be mixed and the composition dispensed.
U.S. Pat. No. 4,676,657 to Botrie, which is hereby incorporated by reference, further discloses a mixing unit is located within the cartridge for mixing the two components as they are forced toward the dispensing nozzle by the plunger. The mixing unit has an inlet port through which the components enter the mixing unit and an outlet port by which the mixed components exit the mixing unit. The mixing unit also includes a mixing body formed of three identical discs. The discs include complementary opposite handed grooves formed on both sides and connected at their outer ends by a port. When the discs are secured together, they define a double spiral passage extending outwardly from the inlet port, through the ports between the discs and ending at the outlet port. Trapped within the spiral passage are passive mixing elements that combine the components. After being mixed along the circular mixing path of the double spiral passage, the composition exits the mixing unit through the outlet port and is delivered to the nozzle for dispensing. While the circular mixing path is acceptable for mixing some components, it may not evenly mix all components no matter their viscosity.
U.S. Pat. No. 5,386,928 to Blette discloses a system for dispensing compositions made from two components. The system includes a side-by-side pair of collapsible reservoirs that fit within a barrel of a pressurized air applicator. As air is admitted into the barrel, the tubes simultaneously collapse to direct components in the tubes through outlet ports and into a static mixer where the components are mixed to a homogeneous composition. The static mixer includes passive mixing elements positioned within the dispensing nozzle. Each tube includes a relatively rigid top and bottom end piece, and the end pieces are coupled together by pin elements for ease of handling and to facilitate dispensing of the contained components. The length of the mixing path in the dispensing nozzle and the number of passive mixing elements positioned within the mixing path are not sufficient to thoroughly mix the components for some applications, especially when the components have different viscosities. While additional static mixers could be placed in the dispensing nozzle to improve the mixing, the result is a very long and cumbersome nozzle that is awkward to place into position and to handle.
The present invention provides a disposable cartridge for a two component systems that can be manufactured economically, that can maintain accurate proportions of the components during use and that can provide efficient mixing of the components prior to dispensing. The present invention also includes a mixing unit that provides accurate and complete mixing of the components.
One embodiment of the invention includes a cartridge assembly for mixing components of a material. The cartridge assembly comprises a component carrying body with a longitudinal axis that extends between a front end and a rear end of the carrying body. The cartridge assembly also comprises a discharge nozzle that is proximate the front end of the carrying body and a mixing unit for mixing the components and delivering the mixed components to the discharge nozzle. The mixing unit includes a plurality of mixing cylinders that each have a longitudinal axis that extends substantially parallel to the longitudinal axis of the component carrying body.
Another aspect of the invention includes a cartridge assembly for mixing components of a material. The cartridge assembly comprises a component carrying body having a front end and a rear end. A discharge nozzle is positioned proximate the front end for dispensing the mixed components. The cartridge assembly also includes a mixing unit for mixing the components and delivering the mixed components to the discharge nozzle. The mixing unit comprises a plurality of spaced cylindrical mixing chambers and at least one mixing element positioned in at least one of the mixing chambers.
Another aspect of the invention includes a cartridge assembly for use with a caulking gun to mix and dispense components of a material. The cartridge assembly comprises a component carrying body having a front end, a rear end and a mixing unit for mixing the components and delivering the mixed components to a discharge nozzle. The mixing unit comprises a mixing body including a mixing path that extends between a front end and a rear end of the mixing body. The mixing path has a first mixing region that is offset from a terminal mixing region in a direction that is opposite the direction of the mixing path. This change in direction provides improved mixing with fewer static mixers than would be required if the mixers were arranged in a straight, linear pattern. This new design can also hold more length of static mixers than the conventional mixer design described, for example, in U.S. Pat. No. 4,676,657 to Botrie.
A further aspect of the present invention includes a cartridge assembly for use with a caulking gun to mix and dispense components of a material. The cartridge assembly comprises a component carrying body having a front end, a rear end and a mixing unit for mixing the components and delivering the mixed components to a discharge nozzle. The mixing unit comprises a mixing body including a mixing path that extends between a rear end and a front end of the mixing body for moving the components from the rear end of the mixing body to the front end of the mixing body and then back to the rear end of the mixing body.
A still further aspect of the present invention includes a cartridge assembly for mixing and dispensing components of a material. The cartridge assembly comprises a component carrying body having a front end, a rear end and a mixing unit for mixing the components and delivering the mixed components to a discharge nozzle. The mixing unit comprises a mixing body including a substantially sinusoidal shaped mixing path.
Further features of the invention will become apparent from the following description of preferred embodiments thereof with reference to the accompanying drawings.